Mail handling container

ABSTRACT

A rectangular shaped container primarily adapted for handling and sorting mail is provided with a hinged top cover comprised of a plurality of foldable sections which may be folded together to collapse the cover for compact storage when it is not being used. Lock flaps on the opposite ends of the cover are inserted into the rear end of pockets formed in the container end walls to hold the cover in its collapsed, storage position; and these same lock flaps are inserted in the front end of the end wall pockets to secure the cover in place when it is swung forwardly over the top of the container to a closed position.

United States Patent Bruckner et al.

[ MAIL HANDLING CONTAINER [75] Inventors: Arnold D. Bruckner, Bowie, Md.; Marlyn D. Johnson, Minneapolis, Minn.

[73] Assignee: Liberty Carton 01., Minneapolis Minn.

[22] Filed: Oct. 15, 1973 [21] Appl. No.: 406,692

[52] US. Cl. 229/34 R; 229/36 R [51] Int. Cl B65d 5/22 [58] Field of Search 229/36, 33, 34; 206/452, 206/4521, 45.24, 45.28

[56] References Cited UNITED STATES PATENTS 2,319,919 5/l943 Clark 229/34 R X 2,608,340 8/l952 Donnell e 229/33 2,793,802 5/l957 Scaturro 229/36 June 17, 1975 2,894,6[8 7/1959 Matteson 206/4528 2.990.995 7/l96l Wessel 229/34 R 3,385.424 5/1968 Thompson et al 229/36 x Primary ExaminerDavis T. Moorhead Attorney, Agent, or Firm-Williamson, Bains & Moore [57] ABSTRACT A rectangular shaped container primarily adapted for handling and sorting mail is provided with a hinged top cover comprised of a plurality of foldable sections which may be folded together to collapse the cover for compact storage when it is not being used. Lock flaps on the opposite ends of the cover are inserted into the rear end of pockets formed in the container end walls to hold the cover in its collapsed, storage position; and these same lock flaps are inserted in the front end of the end wall pockets to secure the cover in place when it is swung forwardly over the top of the container to a closed position.

8 Claims, 6 Drawing Figures PATENTEIJJUNH m5 16691568 I :14. I V

MAIL HANDLING CONTAINER BRIEF SUMMARY OF THE INVENTION This invention is directed to a mail handling container having a closeable, hinged cover which may be collapsed and compactly stored out of the way when mail is being placed into the container during a mail sorting process in a post office, and which may be closed and secured in place over the top of the container when the same container is subsequently used for shipment of the mail placed therein.

These basic objectives have been realized by forming an easily assembled container from a single plank of fiberboard material cut and scored in a predetermined manner to provide a hinged top cover panel comprised of a plurality of foldable panel sections interconnected along fold lines permitting the cover to be collapsed to a compact storage position when it is not being used Lock flaps on opposite ends of a cover panel are utilized to secure it in place in either its collapsed, storage position, or in its fully extended, closed position.

A particularly advantageous feature of this invention resides in the forming of the container to a rectangular shape with end walls having two panel sections folded one over the other to provide a double wall thickness which strengthens the container and defines an open ended pocket between the two panel sections of each end wall. Lock flaps hingedly attached to opposite ends of the outermost one of the cover panel sections are tucked into the rear end of the end wall pockets to hold the cover in its collapsed, storage position. These same lock flaps are tucked into the front end of the end wall pockets to secure the cover in a closed position when it is extended over the top of the container.

A particularly compact storage position for the cover panel in its collapsed condition is achieved by scoring and forming the cover panel so that the innermost panel section of the cover which is hingedly attached to the top edge of the rear side wall of the container has a height dimension no greater than that of the rear side wall. When the cover panel is collapsed, the innermost panel thereof assumes a downwardly folded position in overlying relation to the rear, outside face of the container rear wall in abutting engagement therewith, with the other cover panel sections folded tightly together with the innermost cover panel section. With the aforesaid lock flaps tucked into the rear end of the end wall pockets, the cover panel will be held in a very compact storage position against the outside face of the rear wall of the container where it will not interfere with the placing of mail into the container during a sorting process.

These and other objects and advantages of this invention will become readily apparent as the following description is read in conjunction with the accompanying drawings wherein like reference numerals have been used to designate like elements throughout the several views.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a top, plan view of the fiberboard blank from which the container of this invention is formed and assembled;

FIG. 2 is a front, perspective view of the container in a partially assembled condition with one end wall in the process of assembly;

FIGS. 3 through 5 are perspective views showing the container in successive stages of assembly with the cover collapsed to its storage position; and

FIG. 6 is a front, perspective view of the container with the cover closed and being locked in placev DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, there is shown in FIG. 1 a cut and scored blank of fiberboard material from which the container of this invention is formed. Although fiberboard has been found to be a particularly strong and satisfactory material for the purpose of making the mail handling container of this invention, it is to be understood that other types of bendable material, such as sheet metal may be used. The blank of fiberboard material is generally designated by reference nu meral l, and is cut and scored as shown to provide a bottom wall 2 and a pair of opposed end wall panels 4 and 6. Each of the end wall panels 4 and 6 is comprised of two panel sections 40, 4b and 6a, 6b respectively which are joined together along their respective double score lines 5 and 7. The bottom or innermost end wall panel sections 4b and 6b are hingedly attached to the ends of bottom wall 2 along scored fold lines 8 and I0. Lock tabs I2 and 14 on the outside edges of end wall panel sections 40 and 6a are utilized to hold the end wall assemblies in place in their upright positions of FIGS. 2 and 3 by insertion within complementary slots 16 and 18 in the ends of bottom wall 2. Oval apertures 20a, 20b and 22a, 22b are formed in the end wall panel sections 4a, 4b and 6a, 6b in alignment with each other to provide hand holds through the end walls when the end panel sections are folded over in the assembled condition of FIG 2.

The front, side wall of the container is formed from a front side panel generally indicated by reference numeral 24 which is comprised of a pair of front panel sections 24a and 24b joined together along a fold line 26. Front panel 24 may be folded to an upright position to form the front wall of the container along its hinged fold line connection 25 with bottom wall 2. Angled cuts 28a and 28b are made in the opposite ends of front panel 24 for the separation of panel 240 from panel 24!) in such a manner along fold line 26 that the inward and downward folding of panel 24a over panel 24b will pro vide a front wall with an opening along its central portion for a purpose hereinafter explained. Spaced apart lock tabs 30 on the outer edge of front panel section 24a are utilized to lock this panel section in place against bottom wall 2 by insertion within complementary bottom wall receiving slots 32.

Hingedly attached to the opposite ends of front panel 24 are a pair of inwardly foldable flaps 34a and 34b which are utilized to form part of the end wall structures as explained below. Fingers 36a and 36b of flaps 34a and 34b are cut so as to extend over the top of and not obstruct the hand holds defined by end wall apertures 20a, 20b and 22a, 22b.

The remaining section of the fiberboard blank is a panel generally designated by reference numeral 38 which is cut and scored to provide a rear side wall 40 and a cover panel 44. Rear side panel 40 is hingedly attached to the rear, longitudinal edge of bottom wall 2 along fold line 42. Cover panel 44 is divided into a plurality of panel sections 44a, 44b and 48 which are interconnected along scored fold lines 46 and 50 respectively. Outermost cover panel section 48 serves as a closure panel over the front end of the container in a manner hereinafter explained; and innermost cover panel section 44b is hingedly attached along longitudi nal edge 45 thereof to the top or outer edge of rear side panel 40.

A pair of lock flaps 52a and 52b are hingedly attached to the opposite ends of outermost cover panel section 48 along fold lines 530 and 53b; and for a reason hereinafter explained, fold lines 53a and 53b are parallel to end panel fold lines 5 and 7.

Hingedly attached to the opposite ends of rear wall panel 40 are a second pair of inwardly foldable flaps 54a and 54b which combine with flaps 34a and 34b respectively to provide an additional wall thickness to the end wall assemblies. Flaps 54a and 54b have notches 56a and 56b cut therein to extend around hand hold openings 20a, 20b and 22a, 22b of the end walls.

In the process of assembling the container from the cut and scored blank shown in FIG. 1, panel 38 is first folded upwardly and inwardly so that rear, side wall panel 40 will assume a generally upright position as shown in FIG. 2. Front panel 24 is then folded upwardly and inwardly to a generally upright position, with end wall flaps 34a and 34b being folded inwardly at the same time at right angles to front panel 24. Cooperating end wall flaps 56a and 56b are also folded inwardly to positions outside of their corresponding flaps 36a and 36b as is illustrated in FIG. 2. With the pair of end flaps 34a, 54a in upright positions across one end of bottom wall 2, one end wall is completed by folding end wall panel 4 upwardly and inwardly about its fold line 8 so that end panel section 4b assumes an upright position. End panel section 4a is then folded inwardly and downwardly over flaps 34a, 54a and is locked in place by inserting its lock tabs 12 within slots 16 of bottom wall 2. It will be appreciated that flaps 34a and 540 are thus sandwiched between end wall panel sections 40 and 4b, the utilization of flaps 34a and 54a as part of the end wall structure being facilitated by the alignment of the fold line connections of flaps 34a and 540 with their respective side wall panels 24 and 40 with fold line 8 between end wall panel section 4b and bottom wall 2. Panel sections 40 and 4b cooperate to provide an end wall of two wall thicknesses and define therebetween an open ended pocket within which flaps 34a and 54a are contained. Finger 36a of flap 34a and notch 56a in flap 54a extend over and around aligned slots 20a, 20b so as to provide an unobstructed hand hold extending through the end wall.

The opposite end wall is then formed in the same manner by folding cooperating flaps 34b and 54b inwardly to upright positions along fold line and then folding end wall panel section 6a upwardly and inwardly over panel section 6b and locking it in place within bottom wall slots 18. Panel section 6a will cooperate in a similar manner with upright panel section 612 to define an open ended pocket within which end wall flaps 34b and 54b are contained.

Next, panel section 240 of the front panel 24 is folded inwardly and downwardly over its cooperating panel section 24b and locked in place by inserting its lock tabs 30 within cooperating slots 32 provided along the front edge of bottom wall 2. The completion of this step is shown in FIG. 3. The upright side walls 24 and 40 cooperate with opposed, upright end walls 4 and 6 to form a generally rectangular container, the top of which is defined by the upper edges of the side and end walls. It is to be noted that end wall fold lines 5 and '7 define the upper edges of the end walls. In a like manner, fold line 26 defines the upper edge of front wall 24. With front panel section 24a cut along angles 28a and 28b and folded inwardly and downwardly as shown, the top edge 26 of front panel 24 will be below the adjacent top edges 5 and 7 of the end walls to provide a front opening or recess along a substantial portion of the length of the front wall. This cut-away or recessed portion of front wall 24 clearly shown in FIG. 5 facilitates the placing of pieces of mail in the container with its cover panel 44 open.

To facilitate the loading of the container with mail through its open top, cover panel 44 is collapsed by folding it in accordian fashion along fold lines 45. 46 and 50. As is indicated in FIGS. 3 and 4, these cover panel sections are sequentially folded together in opposite directions in abutting, face-to-face relation with each other along fold lines 45, 46 and 50, with inner most panel section 44b first being folded downwardly and rearwardly. Panel section 440 is then folded up wardly over panel section 44b along fold line 46, and outermost panel section 48 is then folded inwardly and downwardly over panel section 44a along fold line 50. The entire cover panel 44 will thus be disposed rearwardly of container rear wall 40 in the manner shown in FIG. 4. In order to secure cover panel 44 in its collapsed, storage condition, lock flaps 52a and 5212 are folded inwardly to upright positions about their fold line connections with outermost panel section 48 along fold line 53a and 53b to the positions shown in FIG. 4. Lock flaps 52a and 52b are then tucked into the open, rear ends of the pockets formed between end wall panel sections 4a, 4b and 6a, 6b as illustrated in FIGS. 4 and 5. When this operation has been completed, cover panel 44 will be secured in a very compact storage position as illustrated in FIG. 5 with each of its panel sections 44a, 44b and 48 disposed in face-to-face, overlying relation to each other against the rear face of container rear wall 40. The compact folding and storage of cover panel 44 in this manner is greatly facilitated by scoring fold lines 46 and 50 so that they extend parallel to fold line 45 along which the entire cover panel 44 is hingedly attached to rear wall 40 along its innermost longitudinal edge.

It will be appreciated that with cover panel 44 stored in the aforesaid, collapsed condition as shown in FIG. 5 it will be held securely out of the way so as to provide free, unobstructed access to the interior of the container through its open top end and through the cutaway opening in front wall 24. During a mail sorting process, mail of the same zip code is placed in separate, open containers with the open, cover panel secured in its collapsed, storage position as shown In FIG. 5. it will be appreciated that the insertion of lock flaps 52a and 52b into the open rear end of the end wall pocket is facilitated by making the fold lines 530 and 53b of these lock flaps parallel to end wall fold lines 8 and 10. Also, the panel sections 44a, 44b and 48 of cover panel 44 are cut and scored so that innermost cover panel section 44b will have a height dimension which is no greater than that of container rear wall 40. This ensures the compact positioning of the cover panel 44 against the outside face of rear container panel 40 when the cover panel 44 is collapsed to its storage position.

After the containers are filled with mail, they are closed and shipped to predetermined destinations, primarily by air transport, for the distribution of the mail contained therein. For this purpose, lock flaps 52a and 52b are removed from the rear end of the end wall pockets, and cover panel 44 is swung upwardly and inwardly over the top of the container about its longitudinal hinge line connection 45 with container rear wall panel 40. With cover panel 44 lying against the top edges of the container end walls in its closed position as shown in F IG. 6, the fold line connection 50 between outermost cover panel section 48 and section 440 will be positioned even with the front edges of the end walls 4 and 6. This permits outermost panel section 48 to be folded downwardly in overlying relation to the outside of container front wall 24. Lock flaps 52a and 52b are again folded inwardly along fold line 53a and 53b to upright positions coplaner with the end walls as shown in FIG. 6; and the lock flaps 52a and 52b are then tucked into the open front ends of the end walls to secure the cover panel 44 in its closed position. It will be appreciated that with cover panel 44 closed in the aforesaid manner, outermost panel section 48 will serve as a closure panel in overlying relation to the cut-away opening extending across the container front wall 24.

After the closed container reaches its destination, cover panel 44 is very simply opened by simply pulling closure panel section 48 upwardly and outwardly to remove lock flaps 52a and 52b from the end wall pockets, and then folding the entire cover panel upwardly and rearwardly about fold line 45 to the position shown in FIG. 3. Cover panel 44 is then collapsed and stored against the outside face of container rear panel 40 in the manner described above for use in a subsequent sorting and loading operation.

It is anticipated that various changes may be made in the size, shape and construction of the mail handling container as disclosed herein without departing from the spirit and scope of this invention as defined by the following claims.

What is claimed is:

l. A mail handling container formed from out and scored bendable material comprising:

a bottom wall;

a pair of opposed, upright, front and rear side walls extending upwardly from fold line connections with the opposite longitudinal edges of said bottom wall; pair of opposed, upright end walls extending upwardly from said bottom wall at substantially right angles to said side walls and cooperating therewith to form a substantially rectangular container the top of which is defined by the upper edges of said side and end walls, each of said end walls being comprised of a single panel scored along a fold line to provide two end panel sections, one of which is an upright panel section hingedly attached to one end of said bottom wall and the other of which is folded downwardly and inwardly over said one end panel section along said end panel fold line to thereby form end walls of double wall thickness with said end panel sections defining an open ended pocket therebetween, and with said fold line defining the upper edge of said end walls;

a cover panel hingedly attached along one longitudinal edge thereof to the top edge of said rear side wall and disposed in a downwardly and forwardly folded closed position over said container top, said cover panel comprising a plurality of foldable sections interconnected with each other along fold lines extending parallel to said longitudinal hinged edge of said cover panel, said cover panel sections being foldable into a collapsed, downwardly and rearwardly extending condition in overlying relation to said rear side wall, whereby said cover panel may be opened, folded to said collapsed condition and secured in said collapsed condition by inserting said lock flaps into the rear end of said end wall pockets;

a pair of lock flaps hingedly attached to the opposite ends of said cover panel at the opposite, longitudinal free edge thereof and tucked into the front end of said end wall pockets to hold said cover panel in said closed position.

2. A mail handling container as defined in claim 1 wherein:

said front side wall is cut away over a substantial portion of the length thereof with said portion having atop edge below the adjacent top edges of said end walls to provide a front opening which facilitates placing pieces of mail in said container with said cover panel swung to an open position; and

said cover panel includes an outermost panel section hingedly attached to said cover panel along a fold line extending parallel to said hinged longitudinal edge thereof and positioned even with the front edges of said end walls when said cover panel is closed, said outermost panel section being disposed in a downwardly folded position in overlying relation to the outside face of said front side panel and said front opening and serving to close the front side of said container with said cover panel in said closed position; and

said lock flaps being hingedly attached to the ends of said outermost panel section of said cover panel along fold lines which are substantially coplaner with said end walls when said cover pane] is in said closed position.

3. A mail handling container as defined in claim 1 wherein:

each of said end walls includes a pair of flaps hingedly attached to one end of said front side wall and said rear side wall respectively along fold lines in alignment with said fold lines between said end panel upright sections and said bottom wall, said flaps being folded inwardly in upright positions and sandwiched between said panel sections of said end walls.

4. A mail handling container as defined in claim 1 wherein:

the innermost one of said cover panel sections hingedly attached along said longitudinal edge thereof to the top edge of said rear side wall has a height dimension no greater than that of said rear side wall.

5. A material handling container formed from a single blank of fiberboard comprising:

a bottom wall;

a pair of opposed, front and rear side walls extending upwardly from fold line connections with the opposite longitudinal edges of said bottom wall;

a pair of opposed, upright end walls extending upwardly from said bottom wall at substantially right angles to said side walls and cooperating therewith to form a substantially rectangular container, the top of which is defined by the upper edges of said side and end walls, each of said end walls being comprised ofa single panel scored along a fold line lines extending parallel to said end panel fold lines; and

the innermost one of said cover panel sections hingedly attached to the top edge of said rear side to provide two end panel sections, one of which is wall has a height dimension no greater than that of an upright panel section hingedly attached to one said rear side wall and is in a downwardly folded end of said bottom wall and the other of which is position in overlying relation to the outside face folded downwardly and inwardly over said one end thereof in abutting engagement therewith, with the panel section along said fold line to thereby form other cover panel sections folded tightly together end walls of double wall thickness with said end 10 with said innermost cover panel section. whereby panel sections defining an open ended pocket said cover panel is compactly positioned against therebetween and with said fold line defining the said rear side wall in said collapsed, storage posiupper edge of said end walls; tion.

a cover panel hingedly attached along one longitudi- 7. A material handling container as defined in claim nal edge thereof to the top edge of said rear side 5 wherein:

wall, said cover panel being comprised of a plural said cover panel sections are alternately folded toity of foldable panel sections interconnected along fold lines extending parallel to said hinged longitudinal edge of said cover panel and folded together gether in opposite directions into abutting, face-toface relation with each other along said fold lines in an accordian type fold with said cover panel in said collapsed position. 8. A material handling container as defined in claim 5 wherein:

said cover panel is swingable about said hinged longiin a collapsed, storage position in overlying, faceto-face relation to each other rearwardly of said rear side panel; and

a pair of lock flaps hingedly attached to the opposite ends of said cover panel along fold lines, said lock flaps being tucked into the rear end of said end wall pockets and serving to hold said cover panel in said storage position rearwardly of said rear side panel to provide free access to said container through the open top thereof for placing articles therein.

tudinal edge thereof to a forwardly disposed, closed position over the top of said container wherein it rests against the top edges of said end walls, said cover panel being of sufficient width to fully cover the top of said container when fully ex tended and swung forwardly, and said lock flaps being inserted in the front ends of said end wall pockets and serving to hold said cover panel in said closed position.

6. A material handling container as defined in claim 5 wherein:

said lock flaps are attached to the ends of the outermost one of said cover panel sections along fold 

1. A mail handling container formed from cut and scored bendable material comprising: a bottom wall; a pair of opposed, upright, front and rear side walls extending upwardly from fold line connections with the opposite longitudinal edges of said bottom wall; a pair of opposed, upright end walls extending upwardly from said bottom wall at substantially right angles to said side walls and cooperating therewith to form a substantially rectangular container the top of which is defined by the upper edges of said side and end walls, each of said end walls being comprised of a single panel scored along a fold line to provide two end panel sections, one of which is an upright panel section hingedly attached to one end of said bottom wall and the other of which is folded downwardly and inwardly over said one end panel section along said end panel fold line to thereby form end walls of double wall thickness with said end panel sections defining an open ended pocket therebetween, and with said fold line defining the upper edge of said end walls; a cover panel hingedly attached along one longitudinal edge thereof to the top edge of said rear side wall and disposed in a downwardly and forwardly folded closed position over said container top, said cover panel comprising a plurality of foldable sections interconnected with each other along fold lines extending parallel to said longitudinal hinged edge of said cover panel, said cover panel sections being foldable into a collapsed, downwardly and rearwardly extending condition in overlying relation to said rear side wall, whereby said cover panel may be opened, folded to said collapsed condition and secured in said collapsed condition by inserting said lock flaps into the rear end of said end wall pockets; a pair of lock flaps hingedly attached to the opposite ends of said cover panel at the opposite, longitudinal free edge thereof and tucked into the front end of said end wall pockets to hold said cover panel in said closed position.
 2. A mail handling container as defined in claim 1 wherein: said front side wall is cut away Over a substantial portion of the length thereof with said portion having a top edge below the adjacent top edges of said end walls to provide a front opening which facilitates placing pieces of mail in said container with said cover panel swung to an open position; and said cover panel includes an outermost panel section hingedly attached to said cover panel along a fold line extending parallel to said hinged longitudinal edge thereof and positioned even with the front edges of said end walls when said cover panel is closed, said outermost panel section being disposed in a downwardly folded position in overlying relation to the outside face of said front side panel and said front opening and serving to close the front side of said container with said cover panel in said closed position; and said lock flaps being hingedly attached to the ends of said outermost panel section of said cover panel along fold lines which are substantially coplaner with said end walls when said cover panel is in said closed position.
 3. A mail handling container as defined in claim 1 wherein: each of said end walls includes a pair of flaps hingedly attached to one end of said front side wall and said rear side wall respectively along fold lines in alignment with said fold lines between said end panel upright sections and said bottom wall, said flaps being folded inwardly in upright positions and sandwiched between said panel sections of said end walls.
 4. A mail handling container as defined in claim 1 wherein: the innermost one of said cover panel sections hingedly attached along said longitudinal edge thereof to the top edge of said rear side wall has a height dimension no greater than that of said rear side wall.
 5. A material handling container formed from a single blank of fiberboard comprising: a bottom wall; a pair of opposed, front and rear side walls extending upwardly from fold line connections with the opposite longitudinal edges of said bottom wall; a pair of opposed, upright end walls extending upwardly from said bottom wall at substantially right angles to said side walls and cooperating therewith to form a substantially rectangular container, the top of which is defined by the upper edges of said side and end walls, each of said end walls being comprised of a single panel scored along a fold line to provide two end panel sections, one of which is an upright panel section hingedly attached to one end of said bottom wall and the other of which is folded downwardly and inwardly over said one end panel section along said fold line to thereby form end walls of double wall thickness with said end panel sections defining an open ended pocket therebetween and with said fold line defining the upper edge of said end walls; a cover panel hingedly attached along one longitudinal edge thereof to the top edge of said rear side wall, said cover panel being comprised of a plurality of foldable panel sections interconnected along fold lines extending parallel to said hinged longitudinal edge of said cover panel and folded together in a collapsed, storage position in overlying, face-to-face relation to each other rearwardly of said rear side panel; and a pair of lock flaps hingedly attached to the opposite ends of said cover panel along fold lines, said lock flaps being tucked into the rear end of said end wall pockets and serving to hold said cover panel in said storage position rearwardly of said rear side panel to provide free access to said container through the open top thereof for placing articles therein.
 6. A material handling container as defined in claim 5 wherein: said lock flaps are attached to the ends of the outermost one of said cover panel sections along fold lines extending parallel to said end panel fold lines; and the innermost one of said cover panel sections hingedly attached to the top edge of said rear side wall has a height dimension no greater than that of said rear side wall and is in a downwardly folded posiTion in overlying relation to the outside face thereof in abutting engagement therewith, with the other cover panel sections folded tightly together with said innermost cover panel section, whereby said cover panel is compactly positioned against said rear side wall in said collapsed, storage position.
 7. A material handling container as defined in claim 5 wherein: said cover panel sections are alternately folded together in opposite directions into abutting, face-to-face relation with each other along said fold lines in an accordian type fold with said cover panel in said collapsed position.
 8. A material handling container as defined in claim 5 wherein: said cover panel is swingable about said hinged longitudinal edge thereof to a forwardly disposed, closed position over the top of said container wherein it rests against the top edges of said end walls, said cover panel being of sufficient width to fully cover the top of said container when fully extended and swung forwardly, and said lock flaps being inserted in the front ends of said end wall pockets and serving to hold said cover panel in said closed position. 